Step stool



Dec. .5, 1961 E. F. HAMILTON 3,011,585

STEP STOOL Filed March 30, 1959 2 Sheets-Sheet 1 IN V EN TOR. 57m [Ha/m4 70/ I H77 IPA 75.

Dec. 5, 1961 E. F. HAMILTON 3,011,585

STEP STOOL Filed March so, 1959 2 Sheets-Sheet 2 IN V EN TOR. fk/PL 5/01/1411. ra/v,

United States Patent 3,011,585 STEP STOOL Earl F. Hamilton, Columbus, Ind., assignor to Hamilton Cosco, Inc., Columbus, Ind., a corporation of Indiana Filed Mar. 30, 1959. Ser. No. 803,005 7 Claims. (Cl. 182-33) This invention relates to collapsible step stools, or collapsible stools having a group of steps mounted thereon. It has heretofore been proposed to produce such stools without any provision for collapsibility for storage, and by connecting the step assembly to the stool by means of a complex link arrangement.

It is an object of my invention to provide a step stool which will be collapsible for convenience of storage, which will have a simplified construction, and which lends itself to manufacture from sheet-metal and metaltubing. Still another object of my invention is to provide a step stool of attractive appearance which will prove sturdy and durable in use.

In carrying out my invention in its preferred form, I provide a pair of front legs formed from a length of metal-tubing bent into a generally U-shape, the transverse stretch of which rigidly supports a stool back rest. A pair of rear legs also formed from lengths of metaltubing are pivotally connected to the front legs with the upper ends of said rear legs adapted to support the forward portion of a stool seat pivotally mounted on the front legs. Pivotal mounting for the stool seat is provided by a transversely extending seat-supporting rod interconnecting the front legs. Mounted on the seatsupporting rod is a latch member having a pair of arms pivotally connected to a pair of cooperating links pivotally connected to the upper ends of rear legs. Conveniently, this interconnection between the upper ends of the front and rear legs by the latch member and its cooperating links serves to releasably lock the legs in an extended position, and further serves as a means for pivoting said legs with respect to each other during collapse of the stool for storage.

A plurality of steps are rigidly mounted on the front legs at spaced intervals thereon.

The accompanying drawings illustrate my invention. In such drawings:

FIG. 1 is a side elevation of a step stool embodying my invention;

FIG. 2 is a side elevation showing the step stool of FIG. 1 in a fully collapsed position;

FIG. 3 is a longitudinal detail section showing the latch mecham'sm for the legs;

FIG. 4 is a fragmentary plan view of the seat with portions thereof broken away to show the latch mechanism for the legs;

FIG. 5 is a fragmentary side elevation of the seat with portions thereof broken away to show the pivotal seat mounting; and

FIG. 6 is a fragmentary perspective view of a step leg interconnection.

As illustrated in the drawings, my step stool is supported on crossed intersecting legs comprising a length of metal-tubing bent into a substantially U-shape to provide a pair of substantially parallel front legs 12 interconnected at their upper ends by a transverse stretch 14. Conveniently, the stretch 14 is flattened and is rigidly secured to a back rest 16 by a plurality of screws 18. A rear leg 20 is pivotally connected to the outer face of each of the legs 12 as at 22. For reasons that will become more apparent hereinafter, the upper end of each of the legs 20 is flattened and bent rearwardly, as indicated at 24. In order to prevent the stool from slipping on its supporting surface, the lower ends of the legs 3,011,585 Patented Dec. 5, 1961 12 and may be provided with caps formed from rubber, plastic, or the like.

A stool seat 26 in the form of a sheet-metal stamping having a downwardly extending peripheral flange 28 is pivotally connected to the front legs 12. To this end, I provide a seat-supporting rod 30 extending transversely of the seat through openings formed in the lateral stretches of the seat flange 28 adjacent the rear edge of the seat 20, and having its ends received in aligned openings formed in the inner faces of the legs 12. Conveniently, in order to prevent the seat from sliding axially on the rod 30, a bushing 32 is mounted on said rod between each lateral stretch of the flange 28 and its adjacent front leg 12.

The upper ends of the rear legs 20 are interconnected to the front legs 12 by means of a latching mechanism com-prising a generally U-shaped latch member 34 having a transverse stretch 36 interconnecting a pair of forwardly extending arms 38. Each of the arms 38 is provided with an opening through which the seat-supporting rod 30 extends to swingably mount the latch member 34 on said rod in a position such that the transverse stretch 36 is disposed between the seat-supporting rod 30 and the rear stretch of the seat flange 28. Each of the arms 38 extends forwardly from the seat-supporting rod 30 adjacent the inner face of one of the lateral stretches of the seat flange for pivotal connection, as by a rivet 40, to one end of a link 42. The opposite ends of the links are pivotally connected, as by rivets .43, to the upper rearwardly directed ends 24 of the rear legs 20. As illustrated in FIGS. 3 and 4, the medial portions of the links 42 are offset, as at 44, and are provided with notches 46 formed in their upper edges. The notches 46 are adapted to receive dogs 48 formed on the outwardly bent ends 50 of the arms 38 to support the latch member 34 and the links 42 in a latched position for releasably holding the legs 12 and 20 in extended position.

A plurality of steps 52, each in the form of a sheetmetal stamping having a depending peripheral flange 54, are rigidly mounted at spaced intervals on the legs 12, as by rivets 56. Conveniently, to provide greater rigidity to the step-leg interconnections, the lateral stretches of each of the flanges 54 are provided with obliquely extending grooves 58 adapted to abut and mate with the inner faces of the legs 12. As shown in FIG. 1, the lowermost step is disposed toward the front of the stool and thus may also serve as a foot rest when the stool is being used as a conventional stool.

Conveniently, in order to enhance the attractive appearance of the step stool and to provide greater safety therefor, the seat 26 and/ or the back rest 16 may be provided with padded coverings 60 and 62, and the upper faces of the steps 52 may be provided with treads 64.

My step stool is illustrated in FIG. 1 in fully extended position in which it is adapted to be used as a conventional stool, the seat 26 being disposed in a substantially horizontal position parallel with the supporting surface or floor. To adapt the step stool for use as a ladder, it is merely necessary to raise the seat 26 into a substantially vertical position as shown in dotted lines. This is accomplished by applying a lifting force to the front end of the seat to cause said seat to pivot about the seat-supporting rod 39 until the upper face of the seat abuts the forward face of the back rest 16. To releasably lock the seat 26 in this retracted positon, I provide a boss 66 on the underside of the seat adjacent the rear edge thereof. As shown in FIG. 5, during collapse of the seat 26, the boss 66 bears first against the upper and then against the back face of the transverse stretch 36 of the latch member 34, stressing said latch member forwardly. The inherent resiliency of the latch member 34 produces a correspond- 3 ing rearwardly directed biasing force against the boss 66 to releasably hold the seat 26 in its retracted substantially vertical position.

With the seat 26 disposed in the dotted line position shown in FIG. 1, full collapse of the step stool may be easily effected by tilting the stool forwardly on the front legs 12, and then applying a lifting force to one or both of the arms 38 of the latch member 34. This upwardly directed force on the arms 38 pivots the latch member 34 up Wardly about the seat-supporting rod 39, with the links 42 pivoting about their connections to said arms and the rear legs 20 to swing the upper ends 24 of the legs 20 rearwardly. With the step stool in the fully collapsed position shown in FIG. 2, the offset medial stretches 44 of the links 42 bear against the lower edges of the lateral stretches of the seat flange 28 to hold the seat in collapsed position against the back rest 16.

To extend the step stool into the fully extended position shown in full lines in FIG. 1, the above-described sequence is reversed. That is, the stool is tilted forwardly to rest on the legs 12, and the upper ends of the one or both of the legs 20 are pulled forwardly. This causes the .latch member '34, acting through the links 42, to swing downwardly about the seat-supporting rod 30 until the dogs 48 on the latch arms 38 are received in the notches 46 of the links 42, thereby locking the legs 12 and 26) in extended position. The seat 26 is then swung downwardly, pivoting about the seat-supporting rod 39 until the bottom face of the seat engages and rests upon the upper ends 24 of the rear legs 20.

I claim as my invention:

1. A collapsible step stool, comprising a pair of front legs, a pair of interconnected rear legs crossing said front legs and pivotally connected to the outer faces thereof for movement between an extended position in which the upper and lower ends of the front and rear legs are spaced substantially apart and a collapsed position in which said upper and lower leg ends are disposed adjacent each other, a plurality of vertically spaced steps mounted on the front legs, a seat pivotally mounted on a transverse supporting rod mounted on said front legs above their connection to said rear legs and the uppermost of said steps whereby said seat is swingable between an extended position in which it is supported on the upper ends of said rear legs and a collapsed position in which it is disposed rearwardly of said rear legs and steps, and locking means pivotally mounted on said rod and rear legs for releasably locking the front and rear legs in extended position.

2. A collapsible step stool, comprising a pair of front legs rigidly supporting a back rest at their upper ends, a pair of interconnected rear legs crossing said front legs and pivotally connected to the outer faces thereof for movement between an extended position in which the upper and lower ends of the front and rear legs are spaced substantially apart and a collapsed position in which said upper and lower leg ends are disposed adjacent each other, a seat pivotally mounted on said front legs above theirconnections to the rear legs and swingable between a collapsed position substantially parallel to the back rest and an extended position in which it is supported on the upper ends of the rear legs, locking means interconnecting at least one of said rear legs to the front legs for releasably locking them in extended position, and a plurality of steps fixedly mounted on the front legs.

3. A collapsible step stool, comprising a pair of front legs rigidly supporting a back rest at their upper ends, a pair of rear legs crossing said front legs and pivotally connected to the outer faces thereof for movement between an extended position in which the upper and lower ends of the front and rear legs are spaced substantially apart and a collapsed position in which said upper and lower leg ends are disposed adjacent each other, a transversely extending rod interconnecting said front legs above their connections to the rear legs, a seat pivotally mounted on sm'd rod and swingable between a collapsed position substantially parallel with the back rest and an extended position in which it is supported on the upper ends of the rear legs, a latch mechanism mounted on said rod'and pivotally interconnected to the upper ends of the rear legs for releasably locking the front and rear legs in extended position, and a plurality of steps fixedly mounted on the front legs.

4. A collapsible step stool, comprising a pair of front legs rigidly supporting a backrest at their upper ends, a pair of rear legs crossing said front legs and pivotally connected to the outer faces thereof for movement between an extended position in which the upper and lower ends of the front and rear legs are spaced substantially apart and a collapsed position in which said upper and lower leg ends are disposed adjacent each other, a transversely extending rod interconnecting said front legs above their connections to the rear legs, a seat pivotally mounted on said rod and swingable between a collapsed position substantially parallel with the back rest and an extended position in which it is supported on the upper ends of the rear legs, a latch mechanism mounted on said rod and interconnecting the upper ends of the rear legs to the front legs for releasably locking them in extended position, said latch mechanism comprising a pair of links pivotally connected to the upper ends of the rear legs and to a generally U-shaped member pivotally mounted on said transversely extending rod, said links and U-shaped member having cooperating locking means for releasably locking them in a rigid extended position, and a plurality of steps fixedly mounted on the front legs.

5. A collapsible step stool, comprising a pair of front legs rigidly supporting a back rest at their upper ends, a pair of rear legs crossing said front legs and pivotally connected to the outer faces thereof for movement between an extended position in which the upper and lower ends of the front and rear legs are spaced substantially apartand a collapsed position in which said upper and lower leg ends are disposed adjacent each other, a transversely extending rod interconnecting said front legs above their connections to the rear legs, a seat pivotally mounted on said rod and swingable between a collapsed position substantially parallel with the back rest and an extended position in which it is supported on the upper ends of the rear legs, a latch mechanism mounted on said rod and interconnecting the upper ends of the rear legs to the front legs for releasably locking them in extended position, said latch mechanism comprising a pair of links pivotally connected to the upper ends of the rear legs and a generally U-shaped member having a transverse stretch interconnecting a pair of arms pivotally mounted on said rod and pivotally connected to said pair of links, said arms and links having cooperating locking means for releasably locking them in a rigid extended position, means on the seat engageable with the transverse stretch on the U-shaped member to stress said U-shaped member for releasably holding the seat in its collapsed position, and a plurality of steps fixedly mounted on the front legs.

6. A collapsible step stool, comprising a pair of front legs rigidly supporting a back rest at their upper ends, a pair of rear legs crossing said front legs and pivotally connected to the outer faces thereof for movement between an extended position in which the upper and lower ends of the front and rear legs are spaced substantially apart and a collapsed position in which said upper and lower leg ends are disposed adjacent each other, a seat pivotally mounted on said front legs above their connections to the rear legs and swingable between a collapsed position substantially parallel with the back rest and an extended position in which it is supported on the upper ends of the rear legs, locking means interconnecting said front and rear legs and releasably retaining them in said extended position, and a plurality of steps having peripherally extending flanges fixedly mounted on the front legs, the lateral stretches of said flanges having obliquely extending grooves adapted to be received against the inner faces of the front legs.

7. A collapsible stool, comprising a pair of front legs rigidly supporting a back rest at their upper ends, a plurality of vertically spaced steps mounted on the inner faces of said front legs and extending fore and aft thereof, a pair of rear legs crossing said front legs and pivotally connected to the outer faces thereof, said legs being pivotally interconnected below the plane of the uppermost step and movable between an extended postion in which the upper and lower ends of the front and rear legs are spaced substantially apart and a collapsed position in which said upper and lower legs ends are disposed adjacent each other, said rear legs in collapsed position lying in a plane within the fore and aft extent of said steps, locking means operatively interconnecting said front and rear legs for releasably locking them in extended position, and a seat pivotally interconnected adjacent its rear edge to the inner faces of said front legs and swingable between a collapsed position substantially parallel with the back rest and an extended position in which it is supported on the upper ends of the rear legs.

References Cited in the file of this patent UNITED STATES PATENTS 946,352 Hajos Jan. 11, 1910 1,399,835 Willerns Dec. 13, 1921 1,698,243 Schulte Jan. 8, 1929 1,975,062 Johannsen Sept. 25, 1934 2,023,234 Petra Dec. 3, 1935 2,790,486 Hardie Apr. 30, 1957 2,873,793 Garcia Feb. 17, 1959 2,877,075 Kline Mar. 10, 1959 FOREIGN PATENTS 356,269 Great Britain Sept. 7, 1931 

